/*
 * Copyright 2008 Netflix, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.oauth.http;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import net.oauth.client.ExcerptInputStream;

/**
 * An HTTP request or response.
 * 
 * @author John Kristian
 */
public class HttpMessage
{

    public HttpMessage()
    {
        this(null, null);
    }

    public HttpMessage(String method, URL url)
    {
        this(method, url, null);
    }

    public HttpMessage(String method, URL url, InputStream body)
    {
        this.method = method;
        this.url = url;
        this.body = body;
    }

    public String method;
    public URL url;
    public final List<Map.Entry<String, String>> headers = new ArrayList<Map.Entry<String, String>>();
    protected InputStream body = null;

    /**
     * Get the value of the last header of the given name. The name is
     * case-insensitive.
     */
    public final String getHeader(String name)
    {
        String value = null;
        for (Map.Entry<String, String> header : headers) {
            if (equalsIgnoreCase(name, header.getKey())) {
                value = header.getValue();
            }
        }
        return value;
    }

    /**
     * Remove all headers of the given name. The name is case insensitive.
     * 
     * @return the value of the last header with that name, or null to indicate
     *         there was no such header
     */
    public String removeHeaders(String name)
    {
        String value = null;
        for (Iterator<Map.Entry<String, String>> i = headers.iterator(); i.hasNext();) {
            Map.Entry<String, String> header = i.next();
            if (equalsIgnoreCase(name, header.getKey())) {
                value = header.getValue();
                i.remove();
            }
        }
        return value;
    }

    public final String getContentCharset()
    {
        return getCharset(getHeader(CONTENT_TYPE));
    }

    public final InputStream getBody() throws IOException
    {
        if (body == null) {
            InputStream raw = openBody();
            if (raw != null) {
                body = new ExcerptInputStream(raw);
            }
        }
        return body;
    }

    protected InputStream openBody() throws IOException
    {
        return null;
    }

    /** Put a description of this message and its origins into the given Map. */
    public void dump(Map<String, Object> into) throws IOException
    {
    }

    private static boolean equalsIgnoreCase(String x, String y)
    {
        if (x == null)
            return y == null;
        else
            return x.equalsIgnoreCase(y);
    }

    private static final String getCharset(String mimeType)
    {
        if (mimeType != null) {
            Matcher m = CHARSET.matcher(mimeType);
            if (m.find()) {
                String charset = m.group(1);
                if (charset.length() >= 2 && charset.charAt(0) == '"'
                        && charset.charAt(charset.length() - 1) == '"') {
                    charset = charset.substring(1, charset.length() - 1);
                    charset = charset.replace("\\\"", "\"");
                }
                return charset;
            }
        }
        return DEFAULT_CHARSET;
    }

    /** The name of a dump entry whose value is the HTTP request. */
    public static final String REQUEST = "HTTP request";

    /** The name of a dump entry whose value is the HTTP response. */
    public static final String RESPONSE = "HTTP response";

    public static final String ACCEPT_ENCODING = "Accept-Encoding";
    public static final String CONTENT_ENCODING = "Content-Encoding";
    public static final String CONTENT_LENGTH = "Content-Length";
    public static final String CONTENT_TYPE = "Content-Type";
    public static final String DEFAULT_CHARSET = "ISO-8859-1";

    private static final Pattern CHARSET = Pattern
            .compile("; *charset *= *([^;\"]*|\"([^\"]|\\\\\")*\")(;|$)");

}